Method, apparatus and system for use in processing wafers

ABSTRACT

The present embodiment provides for methods and systems for use in processing objects such as wafers, including polishing and/or grinding wafers. Some embodiments provide systems that include a front-end module and a processing module. The front end module couples with a storage device that stores objects for processing. The front-end module can comprise a single robot, a transfer station, and a plurality of end effectors. The processing module is coupled with the front-end module such that the single robot delivers objects from the storage device to the processing module. The processing module comprising a rotating table, and a spindle with a carrier configured to retrieve the delivered object and process the object on the rotating table.

PRIORITY CLAIM

This application is a Divisional Application of U.S. patent applicationSer. No. 11/829,798, filed Jul. 27, 2007, entitled METHOD, APPARATUS ANDSYSTEM FOR USE IN PROCESSING WAFERS, which is a Divisional Applicationof U.S. patent application Ser. No. 11/173,992, filed Jul. 1, 2005,entitled METHOD, APPARATUS AND SYSTEM FOR USE IN PROCESSING WAFERS, nowU.S. Pat. No. 7,249,992, which claims the benefit under 35 U.S.C.§119(e) of U.S. Provisional Application No. 60/585,497, filed Jul. 2,2004, entitled METHOD, APPARATUS AND SYSTEM FOR USE IN PROCESSINGWAFERS, all of which are incorporated herein by reference in theirentirety.

FIELD OF THE APPLICATION

The present application is directed generally toward wafer processingand more particularly to a system and method for wafer processing.

BACKGROUND

Chemical mechanical polishing or planarization (CMP) is a technique ofpolishing materials including semiconductor substrates and filmsoverlying such substrates, which provides a high degree of uniformityand planarity. The process is used to remove high elevation features onfilms created during the fabrication of a microelectronic circuitry onthe substrate, or to remove a layer of film to reveal the circuitryburied underneath the film. In some cases, the process can planarizesemiconductor slices prior to the fabrication of microelectroniccircuitry thereon.

Some conventional chemical mechanical polishing processes uses anapparatus having a single large polishing pad positioned on a platen,against which a substrate is positioned for polishing. A positioningmember positions and biases the substrate to be polished against thepolishing pad, which is rotating. A chemical slurry, which is likely tohave abrasive materials, is typically maintained on the polishing pad tomodify the polishing characteristics of the polishing pad and to enhancethe polishing of the substrate or films.

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects, features and advantages of the present embodiments will bemore apparent from the following more particular description thereof,presented in conjunction with the following drawings wherein:

FIG. 1 depicts a simplified perspective view of a system according tosome present embodiments;

FIG. 2 depicts a simplified overhead view of the wafer processing systemof FIG. 1;

FIG. 3 depicts a more detailed overhead view of the system of FIGS. 1and 2;

FIG. 4 depicts a perspective view of a load station according to somepresent embodiments;

FIG. 5 shows the load station of FIG. 4 from a lower perspective;

FIG. 6 depicts an exploded view of the lower section of the load stationof FIG. 4 according to some embodiments;

FIG. 7 depicts a partial cut-away, elevated perspective view of thelower section of FIG. 6;

FIG. 8 depicts a partial cut-away, lower perspective view of theassembled lower section of FIG. 4;

FIGS. 9-11 depict enlarged views of the springs of the lower section ofFIG. 8;

FIG. 12 depicts an exploded view of the middle and upper sections of theload station of FIG. 4;

FIG. 13 depicting an enlarged view of spring forcing a wafer chuck and awafer guide ring of the middle and upper sections of FIG. 12 together;

FIG. 14 depicts an exploded view of a carrier according to someembodiments;

FIG. 15 depicts a simplified flow diagram of a process for loading awafer into a carrier;

FIG. 16 shows a perspective view of the sensory array employed on themiddle section of the load station of FIG. 4;

FIG. 17 shows a magnified view of the sensory array of FIG. 16;

FIG. 18 depicts a side view of load station according to someembodiments;

FIG. 19 depicts a cross-sectional view of the load station of FIG. 18;

FIG. 20 depicts a cross-sectional view of the load station of FIG. 19,rotated about a Z axis;

FIG. 21 depicts an overhead view of the load station of FIG. 18;

FIG. 22 depicts a cross-sectional view of the load station of FIG. 19with the wafer chuck assembly and the load guide ring, where thecylinder in an extended position;

FIG. 23 depicts an isometric view of a load station according to someembodiments;

FIG. 24 depicts the load station of FIG. 23 rotated about the Z axis;

FIG. 25 depicts a partial cross-sectional view of the load station ofFIGS. 23 and 24;

FIG. 26 depicts a partial cross-section view of the load station of FIG.25, rotated about the Z axis with the cylinder 8 in an extendedposition;

FIG. 27 depicts an overhead view of the load station of FIG. 23;

FIGS. 28A-B depict a simplified block diagram of a control system for awafer processing system according to some present embodiments;

FIG. 29 depicts an overhead view of a system according to someembodiments for processing wafers;

FIG. 30 depicts an isometric view of the system of FIG. 29;

FIG. 31 depicts a simplified, isometric view of a system for processingwafers;

FIG. 32 depicts a simplified, overhead view of a system according tosome embodiments;

FIG. 33 depicts a simplified cross-sectional view of an unload station;

FIG. 34 illustrates the three forces considered during CMP polishing;

FIG. 35 shows a simplified flow diagram of a process for use incalibrating spindle forces;

FIG. 36 illustrates a spindle calibration curve created using the datacollected for bellows pressure or piston pressure versus spindle force;

FIG. 37 depicts a calibration curve corresponding either to theinflatable ring seal pressure that generates a retaining ring force orthe inflatable membrane pressure that generates a corresponding waferforce;

FIG. 38 depicts simplified overhead block diagrams of a two FOUPfront-end module;

FIG. 39 depicts simplified overhead block diagrams of a three FOUPfront-end module;

FIG. 40 shows a simplified cross-sectional view of the turret accordingto some embodiments;

FIG. 41 depicts an isometric view of a pad conditioner;

FIG. 42 depicts an overhead partially transparent view of the padconditioner of FIG. 41;

FIG. 43 depicts a cross-sectional view of the pad conditioner of FIGS.41-42; and

FIG. 44 depicts an under-side view of the pad conditioner of FIGS.41-43.

Corresponding reference characters indicate corresponding componentsthroughout the several views of the drawings. Skilled artisans willappreciate that elements in the figures are illustrated for simplicityand clarity and have not necessarily been drawn to scale. For example,the dimensions of some of the elements in the figures may be exaggeratedrelative to other elements to help to improve understanding of variousembodiments of the present invention. Also, common but well-understoodelements that are useful or necessary in a commercially feasibleembodiment are often not depicted in order to facilitate a lessobstructed view of these various embodiments of the present invention.

SUMMARY OF THE INVENTION

The present embodiment provides for methods and systems for use inprocessing objects such as wafers, including polishing and/or grindingwafers. Some embodiments provide systems that include a front-end moduleand a processing module. The front end module couples with a storagedevice that stores objects for processing. The front-end module cancomprise a single robot, a transfer station, and a plurality of endeffectors. The processing module is coupled with the front-end modulesuch that the single robot delivers objects from the storage device tothe processing module. The processing module comprising a rotatingtable, and a spindle with a carrier configured to retrieve the deliveredobject and process the object on the rotating table.

Other embodiments provide for an apparatus for use in processing wafers.The apparatus can comprises a single turret, a first spindle cooperatedwith the turret, a second spindle cooperated with the turret, a firstmotor cooperated with the turret such that the first motor indexes thefirst spindle using the turret, and a second motor cooperated with theturret such that the second motor indexes the second spindle using theturret independent of the first spindle.

DETAILED DESCRIPTION

The present embodiments provide apparatuses, systems, and methods forprocessing wafers and other objects that are to be processed though oneor more automated processes. For example, the present embodiments areparticularly applicable to Chemical Mechanical Polishing (CMP). CMP isused, at least in part, to planarize and/or polish flat objects such assilicon prime wafers, semiconductor wafers, substrates withmagnetoresistive (MR) or giant magnetoresistive (GMR) heads, and othersimilar objects to be planarized and/or polished. Some preferredembodiments are directed to systems that are relatively compact andinexpensive, and highly reliable. The present embodiments provide veryreliable loading of wafers into the carrier that holds the wafer whileCMP polishing takes place.

FIG. 1 depicts a simplified block diagram of a system 120 according tosome present embodiments. The system includes a processing module 122and a front-end module 124. The front-end module retrieves objects to beprocessed, such as wafers, from a bin or storage elements 126 anddelivers the objects to the processing module 122. The processing moduleprocesses the objects depending on the desired resulting products. Insome embodiments, the processing module 122 polishes the wafers. Theprocessing module can, in some embodiments, additionally and/oralternatively grind the wafers. The front end module 124 can be detachedfrom the processing module such that different front end modules can becooperated with different types of processing modules as fully describedbelow. The processing module 122 and the front-end module 124 operatetogether, and are typically secured together during operation. Thesystem typically further includes structural castings and a framesurrounding the processing module and the front-end module. Someembodiments further include a user interface 174.

FIG. 2 depicts a simplified overhead view of the wafer processing system120 of FIG. 1 according to some embodiments with the processing module122 being secured with the front-end module 124, and two storageelements 126 are secured with the front-end module. FIG. 3 depicts amore detailed overhead view of the wafer processing system 120 of FIGS.1 and 2 according to some implementations. Referring to FIGS. 2 and 3,the storage elements 126 can be substantially any device that storesobjects for processing and can be accessed by the front-end module. Forexample, the storage elements can be front opening unified pod (FOUP)with pod door openers for storing wafers, standard mechanical interfaces(SMIF), cassettes with open cassette loaders, a basin containing fluidwithin which the wafers are stored, and other similar devices. In otherembodiments, a cart carrying the basin is inserted within the front-end124 allowing the basin to be positioned within the front-end allowingprocessed wafers to be inserted into the basin and/or wafers retrievedfrom the basin. The front-end module typically includes one or moremounting faces (e.g., Box Opener/Loader to Tool Standard (BOLTS)interface) that allow the FOUPs, SMIFs, cassettes and other storagedevices to be mounted with the front-end module. In some embodiments,the mounting face(s) is adjustable up and down, and side to side foralignment with the storage device.

The front-end module 124 includes a transport device such as a robot 220that extracts wafers or other objects from the storage elements 126. Therobot control is programmed to retrieve the wafers, transport the wafersto the processing module 122 and return the processed wafers to astorage element. Some preferred embodiments limit the front-end moduleto a single robot 220. By limiting the system to a single robot, thefront-end module can be constructed with a significantly reduced area orfoot print, at a reduced cost, reduced complexity and an increasedreliability. The single robot implementation, however, can be limitingin processing speed and throughput, but the benefits of reduced size,cost, and complexity, and the increased reliability compensates for thetrade off of reduced throughput. Alternative embodiments of thefront-end module, however, can be constructed with multiple robots thatcan be cooperated with the processing module 122 as introduced above.The overall size of the system 120 can be critical for some users as thesquare footage of floor or facility space, such as within a clean room,occupied by the system can be extremely limited and typically relativelyvaluable.

The robot is implemented in some embodiments through a six (6) axisrobot. The six axis robot allows the front-end module to performfunctions that other systems, such as other CMP systems employing commonpolar style robots, cannot perform, or cannot perform without theinclusion of multiple robots. Typically, with standard polar stylerobots the robots operate horizontally and substantially every aspect ofthe positioning of the wafer and the components receiving the wafer arepositioned substantially horizontal (e.g., parallel with the ground).This horizontal limitation restricts the movement of the wafer and theconfiguration of the devices and/or positioned that receive the wafers(such as increasing the size of the system).

Alternatively, the six axis robot utilized in present embodiments allowsfor horizontal movement and placement of the wafer, vertical movementand placement of the wafer, as well substantially any orientation.Components of the system and the carts or FOUPs cooperating with thesystem do not have to precisely align as the six axis robot can be movedto adjust for and/or compensate for the misalignment. During a setup ofthe system, the robot can be manually manipulated to desired locationswhere the positioning, tilt, angle and other parameters set through themanual manipulation are stored for future identification by the robotduring operation.

The robot 220 utilizes end effectors to grasp the wafers duringtransport. In some embodiments, the robot utilizes two separate endeffectors implemented by using tool changers 370, 372. A first endeffector 370 can be utilized for grasping and transporting dry wafers,and the second end effector 372 can be used for grasping andtransporting wet wafers as further described below. A transfer station222 is included in some embodiments within the front-end module wherethe robot 220 positions wafers while switching between end effectors.The transfer station in some implementations receives the wafers in agenerally vertical orientation relative to the ground or the polishingtables, and in some implementations is at a slight angle (e.g., about 15degrees from vertical).

Some embodiments of the front-end module 124 optionally include one ormore single station wafer cleaners 224, and/or measuring stage 226. Forexample, the measuring equipment can include Nova equipment and/or otherequipment. The single station wafer cleaner 224 can be included toperform multi-stage washing and cleaning of processed wafers prior toreturning the wafers to a cassette or FOUP, or other storage. The use ofa single station cleaner saves space typically at the sacrifice ofthroughput. Typically, other CMP systems attempt to optimize throughputand are not particularly concerned with the size of the system. Otherembodiments of the system 120 can include multiple single stationcleaners to increase throughput, or include a series of stations forperforming different stages of cleaning, at the cost of typicallyincreasing the size of the front-end module 124.

One or more electrical cabinets and/or control circuitry 228 can also beincluded in the front-end module to power, control and drive thecomponents of the front-end module 124. The front-end module can includeadditional features and/or devices, such as filtering system to allowcleaned air to be introduced into the system, such as a high-efficiencyparticulate air (HEPA) filtering system. Pre-alignment methods can beincluded to aid in aligning and securing cassettes, FOUPs or otherdevices with the front-end module as well as aligning the front-endmodule 124 with the processing module 122. Similarly, a waferidentification (ID) reader can be included to read an ID from the waferand record the processing of the wafer for many different uses, such asverifying and/or identifying the type of processing to implement throughthe processing module 122, record keeping, stock count, and/or otherpurposes. Some embodiments of the front-end module further include auser interface 174 (typically including a keyboard or other inputdevice, and a monitor). Some embodiments alternatively and/oradditionally provide data ports that allow an external user interface tobe cooperated with the system 120 from a distance. The user interfaceallows the user to control the operation of the system 120, monitor thesystem, retrieve reports and data from the system, and alter theoperation of the system.

As introduced above, the front-end module 124 can be configured with awet basin and/or cassette (e.g., cassette 3214 of FIG. 32 as more fullydescribed below). The wet basin receives the wafers following processingin the processing module 122, and keeps the wafers wet so that slurryand/or other processing chemicals and materials do not dry on the wafer.

The wet basin can be positioned within a basin holder that can raise andlower the basin. In some implementations, the wet basin and holder areincorporated instead of a cleaner 224 and/or a measurement system 226,again maintaining a desirable footprint.

Because the front-end module 124 is removable from the processing module122, and can incorporate many different features and functionality, thefront-end module can be configured for different defined specificationsto meet specific user's needs. The customizing of the front-end moduleallows the system 120 to meet different user demands, provide alternateenhancements and allow customized processing.

The processing module 122 includes a load station 230 and an unloadstation 232, one or more polishing tables 234, 236, and one or morespindles 240, 242. In the embodiment shown in FIG. 2, the processingmodule includes two polishing tables 234 and 236, and two spindles 240and 242. Other embodiments can include three or more polishing tablesand spindles, or only one polishing table and spindle. Each spindleincludes a carrier 244, 246 for carrying wafers for processing. Thespindles 240, 242 are secured with independently rotating turrets 248that rotate and position the carriers 244, 246. A carrier/spindlecontroller 250 is secured with one of the spindles/carriers to drive therotation of both spindles. The carrier controller drives the rotation ofeach spindle independently such that both spindles can be rotatingsimultaneously, the first spindle 240 can be rotated while the secondspindle 242 is stationary, and vice versa. The processing module 122 canoptionally further include a buff table 254 and/or a rinse station 256.Electronic circuitry, power, power control and operational control 260are included in electronic cabinets. The electronic cabinets can beattached as shown, or be detached as separate cabinets from theprocessing module 122. The circuitry couples with the respectivecomponents of the processing module to power and/or control theoperation of the components. Pad conditioners 262 can also be included.The front-end module 124 and the processing module 122 can additionallyinclude other components for wafer processing as is known in the art.

In operation, the robot 220 utilizes, in some embodiments, the twodifferent end effectors, a wet end effector and a dry end effector. Therobot switches between the end effectors depending on the stage ofprocessing for the wafer being grasped. By utilizing the two separateend effectors, the present embodiments operate through a single robottransport 220. Limiting the system to a single robot 220 reduces cost,complexity and provides other advantages. Some alternative embodiments,however, may include multiple robots.

In some embodiments, the robot 220 positions a first end effector (e.g.,wet effector) at an effector storage location, disengages from the firstend effector and engages the second effector (e.g., dry effector) fromits storage location. By engaging the end effector, the robotelectrically and pneumatically couples with and engages the end effectorto supply electrical power and/or control signals. In some embodiments,a tool changer apparatus is incorporated into the robot 220 to allow forthe engagement and disengagement of the effectors. The tool changeincludes a mechanical latching mechanism, in some implementations, toengage the end effectors providing both electrical and pneumaticconnections. In operation for example, the robot utilizes the dry endeffector to retrieve wafers from the FOUP cassette to be processed andto return wafers that have been processed to avoid contaminating theclean environment of the cassette. The robot temporarily places the drywafer at the transfer station 222, switches to a wet end effector,grasps the wafer and transfers the wafer to the load station 230 of theprocessing module 122. In the embodiment shown in FIGS. 2 and 3, thetransfer station is positioned between wafer cleaner 224 and themeasurement system 226.

The wafer is precisely positioned within the load station 230. Theprecision is achieved through several advantageous characteristics andcomponents of the end effector and load station as described in detailbelow. Once positioned in the load station, a wafer sensor 26 (see FIG.16) detects the presence of the wafer and initiates the operation of oneof the spindles, e.g., spindle 246. The turret and spindle controllers250 (which, in some embodiments is implemented in part throughcontrollers as shown in FIG. 28) causes one of the turrets 248 to rotatethe spindle 246 into position over the load station, picks up the waferand moves the wafer to the first polishing table 234 for polishing (orother processing, such as grinding and the like). The robot 220 isnotified by the wafer sensors in the carrier and load station that theload station is empty such that the robot retrieves and delivers anotherwafer to the load station. The turret and spindle controller(s) 250(such as controller 2810, of FIG. 28) then rotate the second spindle 242around to retrieve the second wafer for processing. Because of thedesign of the present embodiments, the spindles operate independentlyallowing improved operation over fixed turrets. For example, oneturret/spindle can be polishing while the other turret/spindle isrotating to load or unload wafers.

Once the polishing and/or processing of the wafer are complete at thefirst polishing table 234, the turret rotates for additional processing.For example, the first spindle 240 may be rotated to an optional rinsestation 256, if incompatible polishing slurries are used on the separatepolishing tables 234, 236. Alternatively, rinsing can also aid inpreventing particle contamination, drying of the processing chemicals,and/or scratches from forming on the wafers during processing. The rinsestation 256 can further be employed to provide a quick rinse, to rinsequick drying slurries, cool the wafer, reduce particles on the wafer,clean the carrier, and/or provide a second place to temporarily place awafer if the processing gets stalled, if the processing on the secondpolishing table 236 takes longer than the process on the first polishingtable, and/or other reasons. The turret can then be rotated to thesecond polishing table 236 for further polishing and/or processing.While the first spindle is shifting the placement of the first wafer,the second spindle 242 can independently rotate to retrieve a secondwafer and position the second wafer at the first polishing table 234.Once the processing of the first wafer is completed at the secondpolishing table 236, the first spindle/carrier 244 can deliver the waferto the buff table 254 to buff the wafer (when the optional buff table ispresent), for example through a water buff to clean the wafer, and/orthen transfer the wafer to the unload station 232. In some embodiments,a sensor similar to the sensor 26 in the load station is used to verifythe presence of a wafer at the unload station. The robot 220 thenretrieves the processed wafer with the wet end effector to move thewafer to the measurement tool 226 or cleaner 224 (when present). Aftermeasurements are complete and the wafer meets predefined criteria, thewafer is shifted to the cleaner 224 (when present) where it is cleanedand dried. The robot switches to the dry end effector, picks up thecleaned and dried wafer and returns the processed wafer to the FOUP 126.Alternatively, when there is no cleaner station 224, the robot continuesto use the wet effector and places the wafer into a wet storage device.

The spindles 240, 242 continue to rotate, typically in a singledirection (e.g., clockwise), to process a series of wafers. This isreferred to as “serial processing.” Alternatively, each spindle can bededicated to a specific polish table, commonly referred to as “parallelprocessing.” For example, the first and second spindles canalternatively be configured for predefined positioning movements of thewafer. For example, the first spindle can be configured to retrieve thewafers from the load station 230, perform the first processing on thefirst table 234, and move the wafer to the rinse station. The secondspindle can perform the second processing at the second table 236 andplace the processed wafer in the unload station 232.

The system 120 can be continuously operated as long as wafers aresupplied for processing. The spindles do not have to be unwound becausethe system employs a rotary union for coupling fluids to the spindlesand a slip ring for coupling electrical power and/or control signals, asdescribed fully below.

In some implementations, the turrets 248 are implemented in separatebearing systems that are concentric. For example, a first bearing systemfor the first spindle 240 can be positioned concentrically within asecond bearing system for the second spindle 242. A first solid columnor tower can house the second bearing system and the first bearingsystem can be housed within the second bearing systems. Further, tubesare included within the tower to deliver fluids through the rotaryunion.

Each turret is driven separately by separate motor, harmonic drive andgear reduction systems (not shown) to move and position the carriers244, 246. FIG. 40 shows a simplified cross-sectional view of the turret248 according to some embodiments that includes first or inner turret4022, concentric second or outer turret 4024, tower housing 4026, rotaryunion 4030 with fluid fittings 4032, bearings 4034, belt or drivepullies or sprockets 4036, 4038, and other elements. The separate motorsimplement independent indexing of the carriers 244, 246 and further canindependently oscillate the spindle/carrier as the wafer is being forcedonto the tables 234, 236 (e.g., oscillating the wafer about half aninch, an inch or other distances over the polishing table as the waferis in contact with the rotating table). The oscillation can beimplemented at variable rates (e.g., the frequency of oscillation(cycles per minute) can be varied), the amount of movement relative tothe tables can be controlled, and the positioning of the wafer radiallyalong the tables can also be independently controlled. The independentoscillation and positioning allows for greater control over thepolishing, grinding or other processing of the wafer. Similarly, therate of polishing is a function of velocity of the polishing pad andcontrolling the positioning of the wafer on the table allows the systemto take advantage of the differences in rotational velocity of thepolishing pad as a function of the radial distance from the center ofthe rotating pad. Single central turret designs of prior art systems donot allow the independent positioning or oscillation of the wafers, andwhen the position of one wafer is shifted, the positioning of otherwafers or carriers are similarly shifted.

A rotary union 4030 couples with the tubes to communicate fluids toand/or from the spindles 240, 242 and between the spindles. The fluidscan include substantially any fluid, such as air, nitrogen, vacuum,water, and other such fluids. A slip ring 2834 (see FIG. 28) is furtherincluded with the turrets to deliver electrical power (at variousvoltages) and electrical signals to communicate to the spindlecontroller 250 and between spindles. In some embodiments, the electricalsignals are communicated through Ethernet connections through the slipring to the spindle controller. Instead of and/or in cooperation withthe slip ring, the system in some embodiments employs wirelesscommunication (e.g., radio frequency (RF), infrared, Bluetooth, andother such wireless coupling) and/or optical communication, such asthrough fiber optical coupling. Further, an inductive coupler, batterypower and/or other similar powering schemes can be employed to deliverpower to the spindles allowing continuous rotation of the spindles.

In some implementations, the system includes one spindle controller 250.Both fluid and electrical signals are communicated to a single spindle(e.g., second spindle 242). From the second spindle, the first spindle240 is electrically coupled with the second spindle and fluid carryingtubing is included to connect the fluids from the second spindle to thefirst spindle. For example, a cable carrier is included in someimplementations to establish the electrical connections between the twospindles and allow control signals to be communicated from the spindlecontroller 250 to the first spindle 240. As such, the first spindle isdaisy chained from the second spindle. In embodiments where the system120 includes a third spindle, the third spindle can be coupled inparallel with the first spindle from the second spindle or further daisychained from the first spindle to receive electrical control signals andpower, and fluids.

In some preferred embodiments, the system is implemented withcommercially available components, and the numbers of componentsincorporated into the system are limited to achieve a system with areduced size, reduced parts, simplified design, and simplifiedoperation, while maintaining a high degree of reliability andconsistency. In achieving these criteria, these specific implementationsare limited to the single robot 220, and only two spindles/carriers 240,242 and polishing tables 234, 236. The single robot 220 where effectorsare switched and a single station cleaner 224 simplify the design andreduce the size of the system 120. Further, the reduced componentssignificantly reduce the cost of manufacture and maintenance.

The present embodiments employ independent spindle indexing whicheliminates the need to backup (counter rotate), e.g., when processingcalls for motions between the multiple processing/polishing tables 234,236. The rotation allows continuous 360-degree motion of wafers aroundthe turret without backing up. However, the spindles can be backed upwhen desired, for example, the spindle 242 can rotate the wafer in acounter-clockwise direction back to the optional rinse station 256following a polishing at the second polishing table 236 prior torotating the spindle in the clockwise direction to deposit the wafer atthe unload station 232 or buff table 254. Independent motion allows forone spindle to be polishing a wafer while the second spindle ispolishing or rinsing another wafer, and/or loading or unloading. Thiscapability improves throughput as well as process options for anoperator, for example, because each step does not have to be the sameduration. Other previous systems had multiple spindles tied together sothat they were required to move simultaneously together, limiting thethroughput and/or process options. The present embodiments allow forgreater flexibility and improved throughput while employing fewerspindles, saving cost and reducing complexity. The independent operationof the spindles further allows the system to rotate the spindles eitherbackwards or forwards to an available station to avoid letting the waferdry and/or keep wafer wet during processing or during an interrupt ofprocessing because some processing chemicals can damage a wafer whenallowed to dry on the wafer. For example, the first spindle 240 canshift the wafer to the rinse station 256 and the second spindle 242could rotate to place the wafer at the buff table, unload station 232 orload station 230 depending on proximity and availability.

The independent spindle indexing is implemented in some embodimentsthrough encoded motor, closed loop servo-control, the combination of theslip ring 2834 (see FIG. 28) at a top of the tower of the turret 248 forelectrical signal and power (e.g., 400V and 24V electrical power, andEthernet signals) and the rotary union at bottom of the tower providesfor the delivery and/or withdrawal of one or more fluids, and/ordistributed control with MMC(s) (Machine Motion controller(s)) locatedon one spindle assembly (e.g., second spindle 242) so that few signallines are to be sent through the slip ring(s). The spindles are wiredand tubed together, in some implementations, to carry electrical signalsand fluids to each spindle. Fiber optic, RF, infrared, wirelessBlueTooth and/or other methods of delivery could additionally and/oralternatively be employed. In some implementations, the rotary union isa four-passage utilities system for water, air, vacuum and Nitrogen.Additional and/or alternative fluids can similarly be utilized. Inembodiments where a third spindle assembly is added, a fifth (or more)fluid passages can be added to achieve adequate volumes. Alternately,the four passage rotary union's capacity is increased. The three or morespindle implementations can be desirable for higher through put, such aswhen polishing times are of relatively short duration.

By utilizing the indexing, precise positioning of the carrier and wafercan be achieved. The present embodiments include an indexing of each ofthe motors rotation and/or the rotation of the turrets 248. Further, theindexing from station to station is employed to monitor the location ofthe carriers and wafers and the processing of the wafers, andcontrolling the oscillation of the carriers. In some implementations, acontroller 2810 (see FIG. 28) controls the indexing of the spindles fromstation to station and the oscillating of the spindles. Spindlecontroller 250 controls the rotation of the spindles, the up and downmotion of the carriers and wafer, back pressure, ring force, and thelevel of downward force applied by the carrier onto the wafer duringpolishing. The spindle controller 250 can be implemented through aprogrammable logic controller (PLC), a microprocessor, or other controldevice. The Ethernet connection through the slip ring reduces the numberof wired and/or channels that has to be communicated through the slipring. Signaling is received by the spindle controller 250 which controlsboth the first and second spindles through a cable carrier betweenspindles. In some embodiments, the spindles further include biasingsprings that bias the carriers 244, 246, and thus the wafer, in an upposition or a position away from polishing tables 234, 236. By biasingthe carriers away from the tables, the system provides a safetymechanism and reduces damage to wafers in the event of temporary or longterm power loss or other problems than can interrupt the control of theprocessing of a wafer. The spindles can further include air poweredboots that can implement the downward movement and force of the carrierand wafers as further described below. Other mechanisms can be employedto move the carrier and wafer between up and down positions and assertthe downward force during processing, such as hydraulics, screw drive,or other such relevant mechanisms.

FIG. 4 depicts a perspective view of a load station 230 according tosome present embodiments. FIG. 5 shows the load station 230 of FIG. 4from a lower perspective looking up at the load station. In thisembodiment, the load station is an edge-contact load station, where theload station contacts the wafer at the edges (defined by thetransitioning area extending between the two generally planar facesurfaces of the wafer) and/or around a relatively small area about theperimeter of the planar face surfaces of the wafer (e.g., typically lessthan about 0.005 times the diameter of the wafer extending from the edgetoward the center). Some embodiments further include a sensor 26 (seeFIGS. 12 and 17) that confirms the wafer is properly positioned on theload station. The load station 230 of the present embodiments simplifiesand provides highly accurate placement of the wafer within the loadguide ring, and further simplifies and ensures accurate placement of thewafer with the carrier 244, 246 of the spindle 240, 242. This accurateplacement is achieved at least in part by allowing a range ofmisalignment between the load station 230 and the carrier 244, and/or amisalignment between the load station 230 and the robot 220.

Still referring to FIGS. 4 and 5, the load station 230 includes a firstor lower section 29, a second or middle section 30, and a third or uppersection 31. FIG. 6 depicts an exploded view of the lower section 29according to some embodiments. The lower section 29 contains linear railassemblies 11, which in some implementations include a linear ballbearing arrangement. The load station is mounted on these linear railassemblies to allow alignment adjustments of the load station in the Xand Y directions. The linear rail assemblies 11 are mounted to railbases 14. One or both of the rail bases are secured with a load stationbase 32 that connects the entire load station 230 to the system 120. Thelower section 29 also contains springs 13 that bias the load station andallow adjustments of the position of the load station 230 in the X and Ydirections, as fully described below. These springs 13, at least inpart, return the load station to a known or centered position.Adjustment knobs 12 are further included in some embodiments to bias theadjustments to positioning and align the load station with the carrier244 and/or robot 220. A cylinder base 15 is secured with one or more ofthe rail assemblies 11 and/or rail bases 14 such that the cylinder baseshifts in the X and Y directions. One or more of the springs 13 aresecured with the rail base 14 to bias the cylinder base 15 to a centerposition (as defined through the adjustment of the adjustment knobs 12).The biasing springs and linear bearing rail array assembly 11 allow forrelatively large amounts of misalignment between the load station 230and the spindle carriers 244, 246, as well as misalignment between theload station 230 and the robot 220.

FIG. 7 depicts a partial cut-away, elevated perspective view of thelower section 29 with the cylinder base 15, linear rail arrays 11 andrail bases 14 assembled and secured with the load station base 32. FIG.8 depicts a partial cut-away, lower perspective view of the assembledlower section 29 with the springs 13 that force the linear rail arraysto a selected center position. FIGS. 9-11 depict enlarged views of thesprings 13 coupled with the linear rail arrays and extending throughand/or secured with the rail bases 14.

FIG. 12 depicts an exploded view of the middle and upper sections 30 and31, respectively. The middle section 30 includes a wafer chuck assembly2. In some embodiments, the wafer chuck assembly contains a wafer chuck4 and wafer guide ring 5. The robot 220 places the wafer no to the waferchuck 4 in preparation for loading into the carrier 244. The wafer chuck4 is seated within the wafer guide ring 5. The wafer chuck 4 and thewafer guide ring 5 are forced together with springs 9 (see FIG. 13depicting an enlarged view of the spring 9 forcing the wafer chuck 4 andthe wafer guide ring 5 together). The wafer chuck 4 and wafer guide ring5 together create a pocket to receive the wafer from the robot 220.Further, in some embodiments, the wafer chuck 4 and wafer guide ring 5are configured such that the wafer only contacts the wafer chuck aroundan edge of the wafer. The wafer chuck 4 is mounted through a base plate6 to a cylinder 8 that lifts the wafer toward and/or into the carrier244, and retracts the wafer chuck assembly 2. The cylinder 8 can beimplemented through substantially any relevant lift, such as a hydrauliclift (e.g., a double-rod hydraulic cylinder), a screw drive or othersuch mechanisms or combinations of mechanisms.

The stationary body of the cylinder 8 is mounted to the base plate 6which connects the lower section 29, middle section 30, and uppersection 31 together. Some embodiments further include one or more wafersensor assemblies 26 in the middle section 30 to detect when the waferhas been properly and/or improperly placed on the wafer chuck 4. Ashield 7 is also included at the bottom of the middle section thatprotects the lift from water and other contaminants.

The upper section 31 contains a load guide ring 1, standoff separators 3and a sprayer 40 (see FIG. 4). Referring to FIGS. 4 and 12, the loadguide ring 1 includes a chamfer 22 along an inner surface. An internalledge defines a carrier load pocket 21. The components of the loadstation 230 that are potentially exposed to processing chemicals aregenerally constructed of corrosion resistant materials, such asplastics, stainless steel, titanium, aluminum and other relevantcorrosion resistant materials. Other components protected fromprocessing chemicals can be constructed of the same corrosion resistantmaterials or other materials, such as steel and other relevantmaterials.

FIG. 14 depicts an exploded view of a carrier 244 according to someembodiments. The carrier includes a retaining ring 24 that has a chamfer28 defined at an exterior, leading edge of the retaining ring 24. Acarrier pocket 25 is defined within the retaining ring to receive thewafer from the load station. In operation, the carrier 244 is seatedinto the load guide ring 1 of the load station 230 to retrieve the waferfrom the load station. The chamfer 28 of the retaining ring 24cooperates with the chamfer 22 of the loading guide ring 1 to providecompensation for misalignment between the carrier 244 and the loadstation 230.

The chamfering 22 of the load guide ring 1, in part compensates formisalignment with the carrier, but further provides at least somecompensation for misalignment of the load station relative to the robot220. In delivering wafers to the load station 230, the robot 220 placesa wafer in the wafer guide ring 5. The configuration of the load stationallows for a predefined amount of misalignment with the robot, and inpart the chamfered upper edge 22 of the wafer guide ring 5 allowscompensation of some misalignment. Similarly, the springs 13 can alsoprovide some adjustment to the misalignment. However, the misalignmenttolerance between the robot 220 and the load station 230 is typicallyless than the misalignment tolerance allowed through the presentembodiments between the carrier 244 and the load station 230. Forexample, in some implementations the misalignment tolerance between therobot 220 and the load station 230 is less than about 0.1 inches, and insome preferred embodiments, less than about 0.05 inches.

In some implementations, the load station 230 is initially aligned withthe carriers 244, 246 using the adjustment knobs 12 defining a centerposition. The robot 220 and/or robot controls are then programmed tomove to the defined centered position. As such, the carriers, in someembodiments, dictate the centered position of the load station 230. Thechamfers 22 and 28 on the load station 260 and carriers 244, 246,respectively, make it simple to adjust the load station 230 by notrequiring the technician to adjust the position of the load station to ahigh degree of accuracy. Also, as the system 120 is operated, thecarrier(s) 244, 246 may become misaligned to the load station. Becausethe load station allows for a relatively large degree of misalignmenttolerance and is accepting of these misalignments, the system cancontinue to be operated for a longer time before being realigned.

In some embodiments, the adjustment knobs 12 can additionally and/oralternatively be utilized to accurately align the load station 230 androbot 220 to within the defined misalignment tolerance (e.g., less thanabout 0.05 inches). This adjusted alignment defines and/or redefines thecenter position of the load station.

The carrier 244 of the spindle 240 is positioned over the load station230 when the carrier is to retrieve the wafer. The carrier is directeddownward in an arching motion onto the load station in preparation forretrieving the wafer. The carrier further includes the chamfer 28 on theouter edge of the retaining ring 24, and the load station 230 includesthe chamfering 22 on the interior of the load guide ring 1. The dualcooperation of the two chamfers, at least in part, allows for thecarrier and load station to be misaligned. Further, by positioning thewafer chuck assembly 2 and load guide ring 1 on the linear rayassemblies 11, the load station can be shifted in the X and Y directionsby predefined amounts depending on the length of the linear rail arrays.The springs 13 bias the load station to the desired center position. Insome embodiments, the misalignment tolerance between the carrier 240 andthe load station 230 can be about 0.25 inches, because the carrier 244applies sufficient force to the load station when misaligned within thetolerance to overcome the spring force from springs 13 and shift theposition of the loading wafer chuck assembly 2 and loading guide ring 1into alignment.

Because the misalignment tolerance between the robot 220 and the loadstation 230 is typically less than the misalignment between the carrier244 and the load station, the present embodiments compensate for thesetwo differences in variation, by mounting the load station on the linearrail arrays 11. The linear rails allow the load station to slide in boththe X and Y axes. As a result, when the misalignment of the carrier 244and the load station 230 is within the tolerance, the chamfering 22 and28 of both the load guide ring 1 and the retaining ring 24,respectively, cause the load station to roll along the linear railarrays in the X and/or Y direction to align the carrier 244 and the loadstation 230. This shift in positioning of the load station, however, canadversely affect the alignment of the load station 230 with the robot220. Therefore, the load station is biased to the predefined centerposition for alignment with the robot. Following a shift of the loadstation 230 by the carrier 244, once the carrier is withdrawn from theload station, the load station returns to the center position throughthe biasing.

In some embodiments, the load station includes one or more, andtypically a plurality of springs 13 to implement the biasing. The loadstation can further be centered at the center position (typicallydefined by the alignment with the carrier) by adjusting the adjustmentknobs to shift the positioning of the anchoring of the biasing springs13 and/or the tension on the one or more springs 13 to center the loadstation 230 in alignment with the robot 220, within the predefinedtolerance as further described fully below.

In some prior art systems, screws would have to be loosened, allowingthe load station position to be adjusted, then the screws would besecured to maintain the positioning. The present embodiments avoid thiscomplicated and cumbersome process by allowing the tension within thebiasing of the load station 230 to be adjusted.

In removing the wafer from the load station, the carrier is positionedover the load guide ring 1 and is pressed into the carrier load pocket21 (with the chamfering 22 and 28 cooperating for alignment). Thecylinder 8 drives or elevates the wafer chuck assembly 2 and the waferthrough an inverted truncated cone aperture in the load guide ring 1,aligning the wafer with the carrier 244, and into carrier pocket 25. Theinverted truncated cone in the load guide ring allows for misalignmentbetween the wafer, wafer chuck and load guide ring, such that as itpasses through the guide ring the wafer is aligned with the carrier. Insome embodiments, the load guide ring 1 further includes one or morecut-outs or recesses 420, and typically a plurality of cut-outspositioned about the circumference of the load guide ring. The cut-outs420 provide additional areas into which the retaining ring 24 of thecarrier 244 can extend due to swelling or expanding of one or both ofthe load guide ring 1 and retaining ring 24, often as a result ofabsorbing fluids and/or expansion from heat. The spacing tolerancebetween the inner diameter of the load guide ring 1 and outer diameterof the retaining ring 24 is precise. The cut-outs effectively provideareas into which the retaining ring 24 can bend or bulge duringretrieval of the wafer from the loading station and reducing thefriction between the retaining ring 24 and the load guide ring 1 suchthat the retaining ring is more easily removed from the load guide ring,reducing the likelihood of the retaining ring becoming lodged and stuckin the load guide ring 1.

In other systems, reliable loading often required extremely precisealignment of the spindle (and carrier) center with the load stationcenter in both the X and Y directions in the horizontal plane of theload station. Typically, the spindle and load station centers of theseother systems need to be aligned to one another within a tolerance of atmost about 1/64 of an inch. As such, frequent realignments of thesecomponents are required in these other systems during productionoperation to maintain reliable loading and to avoid breaking valuablewafers.

The present embodiments, alternatively allow for a relatively muchgreater misalignment tolerance. For example, in some implementations,the misalignment tolerance between the carrier 244 and the load station230 can be about ¼ of an inch, which is about 16 times more tolerantthan other systems. This simplifies aligning, reduces the frequency ofperiodic realignments, improves throughput, improves reliability,reduces wasted wafers and provides other significant advantages.

The capacity to handle misalignments between carrier and load stationare achieved, at least in part, by machining matching chamfers 22 and 28into the load guide ring's load pocket 21 and carrier's retaining ring24, respectively. The outer diameter of the retaining ring engages andaligns the carrier in the load pocket. These chamfers 22, 28 allow forthe misalignment within a predefined tolerance (e.g., about 0.25inches), and additionally the wafer chuck assembly 2 and load guide ring1 are free to move in X and Y directions on the linear rail assemblies11, allowing the load station to freely move and align with the carrier.After the load sequence, the load station 230 shifts back to a knowncenter position by use of springs 13. The return of the load station tothe known position after loading the wafer into the carrier aligns theload station 230 with the robot 220 within the predefined misalignmenttolerance to ensure the next wafer can be loaded into the load station230 by the wafer robot 220. The present embodiments allow for thecontinuous operation of the system 120 to load wafers in the carriers244, 246 with minimal, and preferably zero failures and without repeatedrealignments, as is often required in other systems.

FIG. 15 depicts a simplified flow diagram of a process 1510 for loadinga wafer into a carrier 244. In loading a wafer in the carrier, severalmoveable mechanical elements are coordinated in space and in time toachieve a successful wafer loading. In step 1520 a wafer is selected bythe robot 220 from a storage element 126 by an edge-contactend-effector. In some embodiments, vacuum holding on the back of a wafercan also be used, but may not be desirable for some processes. In step1522 the wafer is moved by the robot to the wafer chuck 4 and placedinto the wafer guide ring 5. The wafer chuck 4 and wafer guide ring 5are designed, in some preferred embodiments, with relief cuts toaccommodate edge contacting end effectors. In step 1524 it is determinedwhether the wafer sensor assembly 26 confirms that the wafer iscorrectly placed. The sensor assembly communicates the results to acentral control center (e.g., control center in electronics 260). Insome embodiments, the wafer sensor 26 is a passive type sensor thatoperates in a very wet environment. The wafer sensor 26 is described indetail below.

If the wafer is not present, the process returns to step 1524 to awaitthe detection of a wafer. Once the wafer sensor 26 detects a wafer instep 1524, the process continues to step 1526 where the carrier (e.g.,first carrier 244) is moved into position above the load station 230 andthe load guide ring 1. In step 1526, the carrier 244 is lowered into theload guide ring, seating it into carrier load pocket 21 of the loadstation. In some embodiments, the process includes an optional step1530, where the backside of the wafer is sprayed with deionized waterusing sprayer 40 (see FIG. 4). Wetting the backside of the wafer canassist in loading the wafer into the carrier 244 via water tension, aswell as can have useful affects during processing.

In step 1532, the cylinder 8 lifts the wafer, wafer chuck 4, and waferguide ring 5 until the wafer guide ring contacts the bottom of the loadguide ring 1. Because the wafer, wafer chuck 4 and wafer guide ring 5are raised together, the wafer stays centered on the wafer chuck andwithin the wafer guide ring. Even though the wafer guide ring 5 is nowstopped, and in some embodiments, positioned against the bottom of theload guide ring 1, the wafer chuck 4 can continue to lift the wafer upthrough the load guide ring 1 because the wafer chuck 4 and wafer guidering are connected by tension springs 9 or some other biasing, whichstretch to accommodate the separation. As the wafer passes through theload guide ring 1, it is aligned with the carrier 244. In step 1534, thewafer is pushed up until it is seated into the wafer carrier pocket 25.Splined, segmented, and sloped contacts on the load guide ring 1 and onthe wafer chuck 4 are included in some embodiments to allow positioningand reliable alignment of the wafer on the carrier, while onlycontacting the edges of the wafer.

In step 1536, a carrier holding method is applied to hold the wafer inplace in the carrier pocket 25. In some embodiments, the holding methodis implemented through a vacuum, however, other holding methods can beemployed. In step 1540, the correct loading of the wafer is confirmed bya carrier sensor (e.g. vacuum level sensor), and the positioning iscommunicated to a control center. In step 1542, the cylinder 8 of theload station 230 lowers to a down position. As the cylinder lowers, thewafer guide ring 5 and the wafer chuck 4 are forced back together bybiasing (e.g., through springs 9). The carrier lifts from the loadstation (in some implementations simultaneously with the lowering of thecylinder) with the wafer and moves to the polishing position, thuscompleting the operation of loading a wafer on the carrier 244. As thecarrier rises from the load station, springs 13 move the wafer chuckassembly 2 and load guide ring 5 (and/or the load station 230) back to aknown and/or centered position. The chuck and guide ring are lowered.The load station is now ready to receive the next wafer.

FIG. 16 shows a perspective view of the sensory array 26 according tosome embodiments, which can be employed on the middle section 30 of theload station 230. FIG. 17 shows a magnified view of the sensory array 26of FIG. 16. In some embodiments, the sensor array 26 is designed tooperate reliably in very wet environments and tolerates variations inwater supply pressure. Other sensors of this type are sensitive to asupply pressure of a liquid. The present sensory assembly, however,operates accurately within a wide range of pressures, for example, atpressure between about 10 to 80 psi, and generally operate between 20 to60 psi (nominal is 30 psi).

The sensor assembly 26 consists of sensor cap 16 mounted atop sensortube 19, which is mounted to sensor base 20. During operation, water issupplied to the lower end of the sensor tube 19, so that it flows up thesensor tube and out a top of the sensor tube (not shown). This flowpushes on the sensor cap 16 upward from its down position and up againststop 17. In some preferred embodiments, only a small amount of waterpressure is required to lift the sensor cap to the stop. The stop 17further allows a wide range of pressures to be used, because as waterpressure is increased, the sensor cap is still held in place by thestop. The stop 17 is adjustable to achieve a desired lift of the sensorcap 16.

In some embodiments, the sensor cap has a small orifice or orifices,and/or porous material at the top, which allows some amount of water toflow out of the top. When a wafer 1720 (see FIG. 17) is lowered downagainst the sensor cap 16, the wafer's weight pushes the sensor capdown. Because of the water escaping through the hole/holes and/or porousmaterial the wafer is maintained on the surface of the water such thatthe wafer does not touch the cap, and as such only water touches thewafer. A target flange 18 is firmly secured with a base of the sensorcap. On the base there is a proximity sensor 70 to sense the presence ofthe target. The proximity sensor can be implemented throughsubstantially any proximity sensor, such as an inductive sensor or othersuch sensors. When the sensor cap 16 and target 18 are in the upposition, the proximity sensor 70 does not sense the target meaning nowafer 1720 is present. Alternatively, when the sensor cap and target arein the down position, the proximity sensor 70 senses detects the target18 identifying that a wafer is present in the load station 230.

Some preferred embodiments employ chamfered edges 22 and 28 on the waferguide ring 1 and the retaining ring 24, respectively, so that the robot220 and wafer carrier 244 have some latitude in positioning relative tothe load station 230. The wafer chuck 4 and load guide ring 1 include,in some implementations, segmented shoulders so that the wafer iscontacted only at the edge of the wafer, while still allowing accurateplacement of the wafer into the carrier 244 during loading.

In some embodiments, low friction X-Y self alignment with the carrier isemployed by way of low friction linear rail assemblies 11. Additionally,precise X-Y alignment is achieved through adjustment knobs 12.Mechanical adjustment of the wafer load station X-Y position isimplemented, in some implementations, by firmly mounting the loadstation base 32 support structure to the rigid frame of the system ortool 120. The adjustment knobs 12 are then used to set the load station230 to a desirable centered position to assure loading of two or morespindles, where the alignment of the spindle to load station centers arewithin predefined thresholds (such as within about ¼ of an inch).Similarly, the adjustment knobs 12 are then used to position the loadstation to the desirable centered position to assure alignment with therobot 220 to within a predefined tolerance and thus providing properplacement of the wafer in the load station 230.

The linear rails assembly 11, in some embodiments, is implementedthrough two rails positioned orthogonally on opposite sides of a railbase 14. Each rail cooperates with a rail block that slides or rollsalong the rails. In some embodiments the rail block includes one or moreball bearings through over which the rails roll. The first rail (e.g.,rail closest to the base 32) is positioned along a first axis (e.g., Xaxis), while the second rail is positioned along a second axis (e.g., Yaxis) orthogonal to the first axis. The rails can be configured to matewith the rail block so that the rails engage the block, such as throughtapered grooves in the block that receive the rails that are similarlytapered to correspond with the grooves of the blocks. The first railblock can be secured with the first rail base (e.g., the rail basecloses to the lower section base 32) and the first rail can be securedwith the second rail base such that the second rail base moves along thefirst axis. The second rail is further secured with the second rail baseon an opposite as the first rail. The second rail block coopered withthe second rail can then be secured with the cylinder base 15 allowingthe cylinder base to move along the second axis achieving movement ofthe load station 230 in both the orthogonal directions through themovement of the second rail base 14

The rails and rail blocks of the linear rail assembly can be constructedof steel, stainless steel, aluminum, plastic, an alloy, one or morepolymers, combinations of materials and/or other relevant materials. Insome instances the rail block can include bearings or other frictionreducing means, such as a plastic, Teflon or other coating, that aid inthe rolling or sliding of the rails through the block. The rails and/orrail block can include stops that prevent the excessive movement of therails relative to the block and/or the rail base 14. Typically, the railassembly 11 is positioned in the lower section 29 of the load stationassembly 28 that is positioned below a deck or floor of the processingarea of the processing module 122 to limit and/or avoid contact withpotentially corrosive or damaging chemicals. Further in someimplementations, the rail assembly 11 is encased within a protectivecover to further protect the assembly.

The adjustment knobs in some embodiments are implemented throughthreaded members that threadedly engage an anchoring 920 of a biasingspring 13. Referring to FIGS. 7, 9 and 11, by rotating an adjustmentknob the threading provides precision adjustments of the biasing springanchoring 920 along a groove 922 on one side of the biasing springshifting the center biasing position and thus the position of thecarrier load pocket 21 of the load station 230. The lower section 29 ofthe load station assembly 28 can include one or more adjustment knobs 12to adjust the anchoring positions of one side of the biasing springs 13.

The spring return system, implemented in some embodiments through thebiasing springs 13 and linear rail assemblies 11, return the loadstation 230 to a known position after the wafer is loaded into thecarrier, allowing the robot 220 to load the next wafer into the waferguide ring. Referring to FIGS. 8 and 10, in some implementations, thebiasing springs 13 are positioned at slight angles relative to verticalto reduce or avoid inadvertent pulling toward one direction or anotherwhen the load station is at a centered position.

Referring to FIGS. 4, 12 and 13, a biasing or spring system 9 connectingthe wafer chuck 4 and wafer guide ring 5 biases the chuck and guide ringdefining such that a pocket is formed to receive the wafer when thecylinder is in a down position. The spring system 9 further allows thewafer chuck 4 (and wafer when positioned within the load station) toextend into the load guide ring 1 and up to the carrier 244 duringlifting by the cylinder 8 and be pulled or biased back into positionupon retracting the cylinder. The wafer sensor assembly 26 (see FIGS. 12and 16), which in some preferred embodiments is substantially immune tochanges in incoming water pressure, accurately detects the presenceand/or positioning of a wafer, and contacts the wafer only with water,preventing scratches or particulate damage, while the flow of waterflushes or purges the sensor such that the sensor does not clog.

The present embodiments can be easily and quickly adjusted for differentobjects for processing. For example, the present embodiments are quicklyconverted for wafers of various diameters (e.g., 100 to 400 mm diameter,and other diameters) by simply changing a few parts on the load station230 and the carrier size. The parts to be swapped typically include theload guide ring 1, the wafer chuck 4, the wafer guide ring 5, and thecarrier 244.

FIG. 18 depicts a side view of load station 230 according to someembodiments. The wafer chuck 4 and wafer guide ring 5 are in a downposition separated from the load guide ring 1. FIG. 19 depicts across-sectional view of the load station 230 of FIG. 18. FIG. 20 depictsa cross-sectional view of the load station 230 of FIG. 19, rotated aboutthe Z axis. FIG. 21 depicts an overhead view of the load station 230 ofFIG. 18. FIG. 22 depicts a cross-sectional view of the wafer chuckassembly 2 and the load guide ring 1, with the cylinder 8 in an extendedposition driving the wafer chuck 4 into the load guide ring 1, and thewafer guide ring 5 in contact with the load guide ring 1. A bellows seal2320 is shown around a portion of the cylinder 8 to protect the cylinderand to limit or prevent water and slurry from seeping below the bearingrail assembly, table and system 120.

FIG. 23 depicts an isometric view of a load station 230 according tosome embodiments. FIG. 24 depicts a side plane view of the load station230 of FIG. 23 rotated about the Z axis. FIG. 25 depicts a partialcross-sectional view of the load station 230 of FIGS. 23 and 24. FIG. 26depicts a partial cross-section view of the load station 230 of FIG. 25,rotated about the Z axis with the cylinder 8 in an extended position.FIG. 27 depicts an overhead view of the load station 230 of FIG. 23.

The unload station 232 can be configured similar to that of the loadstation 230. In some embodiments, however, the unload station does notinclude a cylinder for raising and/or lower a portion of the station.The unload station 232 in some implementations does include one or moresprayers 3276 (see FIG. 32) that keep the processed wafers wet untilretrieved by the robot 220 using the end effectors. The sprayers canfurther wash the carriers 244, 246. For example, sprayers can bepositioned about the perimeter of the unload station to spray the waferand/or carrier, and/or one or more sprayers in the center of the unloadstation to spray the underside of the wafer. The robot 220 removes thewafer from the unload station and places the wafer into storage,following some measurement and/or cleaning in some implementations.Implementing the robot through the six axis robot allows the system totilt the disk to let accumulated water on the surface face of the diskto run off. Some embodiments of the system include a receptacle or drainproximate the unload station over which the wafer is tilted such thatthe pooled or accumulated water is received upon tilting the wafer tolimit the amount of water or other liquid dripped over the processingand/or front-end modules.

The system 120 can, in some implementations further include componentsfor measuring and/or calibrating the spindle force, wafer force and/orretaining ring force as applied through the carriers 244, 246. Forexample, the unload station 232 in some embodiments includes one or moreload cells 276 (see FIG. 2) for use in detecting pressures applied bythe carrier and/or wafer when the carrier deposits the processed waferinto the unload station as fully described below.

FIG. 28 depicts a simplified block diagram of a control system 2800 forthe system 120. The control system 2800 includes a central controller2802, which can be implemented through a process, micro-process,computer, other control systems, and other such controller and/orcombinations thereof. The central controller 2802 includes a pluralityof input/output ports, such as SBC video, keyboard, mouse and other userinterface input/output port 2804, and external communication port 2806(such as an Ethernet port). The central controller can includeprocessing circuitry and/or sockets, such as MMC/PC Block I/O socket2810, MMC/PC Analog socket 2812, RS-485 PCI card socket 2814, and othersuch processing capabilities.

The central controller couples with an operator interface 2820, to allowusers to control the system, alter operations, upgrade the system, toretrieve data stored by the central controller and other such access. AnEthernet hub 2822 couples with the Ethernet connector 2806 of thecentral controller to distributed control signals to the cleaner controlsystem 2824 that controls the wafer cleaner 224 in the front-end module124, to a measurement control system 2826 that controls the measuringstage 226, a robot controller 2830 that controls the operation of therobot 220, an Fab Service connection, and other similar controllers. Insome preferred embodiments, the Ethernet hub 2822 further couples with aslip ring 2834 of the turret 248 for powering and/or controlling thespindles 240, 242 and carriers 244, 246. The slip ring distributes thecontrol signals through an MMC stand-alone motion controller and PLC 250(which, in some embodiments, can be implemented for controller of FIG.2) to the drives of the spindles, such as to a first inverter 2840 andmotor 2842, to control the spindle rotations. The control signals can bedaisy chained from the first inverter to a second inverter 2844 to bedelivered to a second motor 2846. The daisy chaining can continue forany number of spindles. The slip ring can further direct control toother components, such as block I/O 2850 and other components. In oneembodiment, the Ethernet hub 2822 is implemented through a four or eightport hub or switch, however other such switching devices can beemployed.

A communication channel 2852, such as a fiber optic link, can couplewith the port of the controller 2810 to the turret controllers 2854,2856, that control the turret motors 2858 and 2860. In some embodiments,the MMC Analog 2812 provides at least some control of the rotations ofthe turrets. Pad sweep controllers 2862, 2864 can also couple with thefiber link to control the pad sweep motors 2866, 2868. Similarly, padrotator controllers 2870, 2872 can communication with the centralcontroller 2810 over the fiber link to control the pad rotation motors2874, 2876. Data break out terminals 2880, 2882, 2884 can couple withthe PCI card port 2834 of the central controller 2810 to distributecontrol to polishing table inverters 2886 and 2888, and a buff tableinverter 2890.

FIG. 29 depicts an overhead view of a system 2910 according to someembodiments for processing wafers. FIG. 30 depicts an isometric view ofthe system 2910 of FIG. 29. The system 2910 includes the processingmodule 122 and the front-end module 124. The processing module 122includes three spindles 2920, 2922 and 2924, each with a carrier 2930,2932 and 2934. Each spindle is coupled with a turret in the tower suchthat each spindle is independently operated and indexed. The system 120further includes other similar components as the system shown in FIGS.1-3, such as the robot 220, the storage elements 126, load station 230,first and second polishing tables 234, 236 and other such components.The front-end module 124 further includes a scanner, however, the areaoccupied by the scanner can be utilized to incorporate other devicesinto the system 2910, such as a spin station, metrology, or otherdevices. Further, the transfer station is positioned generallyvertically (e.g., 15 degrees from vertical) relative to the deck of thesystem.

In some embodiments, the system 120 and/or 2910 can be employed toprovide fully automated, cassette to cassette, chemical-mechanical waferpolishing for wafer reclaim. For example, in one implementation, thesystem 120/2910 can be configured to operate on wafers with sizes of 300mm in diameter, notched, with nominal thickness equal to about 800microns, and/or 200 mm in diameter, notched, with nominal thicknessequal to about 725 microns. The system would have a tool footprint ofabout 2.8×2.0 meters, 5.6 square meters, and operate at 208 Volts3-Phase, 150 full load Amps, 50-60 Hz, clean dry air at 6.2 bar, 170L/min, nitrogen at 5.5 bar, 14 L/min, a vacuum at 508 mm of mercury, 85L/min, an exhaust at about 14 m³/hour at 125 Pascal, and utilizedeionized water at 2.1 bar, 11 L/min. This system would be SEMI S2, S8and CE compliant.

Further, the system can be easily converted from processing 200 mmdiameter wafers to other sized wafers (e.g., to 300 mm diameter wafers).For example, in reconfiguring the system 120, a user would switch out inthe load station 230 the load guide ring 1, chuck 4, and wafer guidering 5; in the unload station 232 the unload guide ring; in the carriers244, 246 the retaining ring; and in the front-end module the endeffectors and cassettes. When altering at least the unload station 232,the sprayers 3260 (see FIG. 32) would be shifted to the correspondingdiameter, and in altering the load and unload stations, the sensor wouldbe shifted between sensor positions (e.g., 3280 and 3282 (see FIG. 32)for 300 mm and 200 mm diameter wafers, respectively).

In operation, such a configured system can achieve a throughput forsingle side polishing of about 30 to 40 wafers per hour, at the firstpolishing table (Platen 1) 234 for a time equal to about 60 seconds, andat the second polishing table (Platen 2) 236 for a time of about 30seconds. Similarly, the system could provide a throughput for doubleside polishing at a rate of about 15 to 20 wafers per hour with the samepolish times as listed above. This system could expect to have a highreliability. For example, the system would operate continuously for atleast 500 hours MTBF, and maintain an 80% confidence interval, ascalculated per SEMI specification, with greater than about a 90% uptime, with an MTTR less than about 4 hours. In some preferredembodiments, the system would include factory host communicationsoperating with Ethernet, using SECS/GEM Protocol, with recipe uploading.

Some embodiments of the systems 122/2910 can employ polish table (e.g.,2 each) with a granite surface, having a diameter of about 32 inches(812 mm), and operated at table temperature controls between about 10 to90 degrees Celsius, and at speed ranges between about 10 to 180 RPM.

Pad conditioners 262 can be utilized in some implementations. FIGS.41-44 depict an isometric, an overhead partially transparent,cross-sectional, and under-side views, respectively of pad conditionersaccording to some embodiments. The conditioners can be implementedthrough diamond disks, nylon brushes and other relevant conditionersdepending on the type of polishing or grinding pad used on each table.The conditioners include a gear box 284, 286 that typically have arelatively low profile 4120 to allow the independently controlled androtated spindles 240, 242 to index over the pad conditioner withoutcontacting the conditioner. The gear box can be implemented as wormdrive type gear box to operate the conditioning disk or brush. Further,the motor 287 and 288 to operate or rotate the conditioning disk orbrush is moved back along the arm from the conditioning end with aflexible shaft cooperating between the motor and the gear box. Someother previous systems commonly employ the motor and gear box at theconditioning end of the conditioner, which would interfere with themovement of one or both spindles and carriers. This configuration alsoallows the motor to be contained and away from the elements of thepolishing process. The downward force is applied to the conditioningdisk or brush to condition the tables 234, 236, is through bellows 4322or other relevant devices, which is in some implementations isco-located with the motor. For example, one metal bellow 4322 can bepumped up to push the arm down and one bellow 4320 can be used to raisethe arm up. Employing bellows provides rapid response, precisecalibration and avoids hysteresis. The arm is rotated by a servo-motorand harmonic drive beneath the deck that rotates the arm into position,and is programmed for where the conditioning is to take place, how fastthe disk or brush is rotated, and how much force is applied.

Some embodiments further include a wet dish into which the conditioningdisk or brush are placed while not in use and in a parked position. Thewet dish, such as a dish of water or other relevant liquid, avoidsdrying out of the conditioner, and allows cleaning of the conditioner.The water dish can additionally include a brush or bar that can berotated or rubbed against the conditioner to clean the conditioner. Insome implementations an ultrasonic cleaner is cooperated with the waterdish to further aid in cleaning the conditioner.

For example, pad conditioners (2 each, 1 per platen) are, in someembodiments, 4 inch diamond disk or nylon brush types, that operate atdevice speed ranges between about 5 to 100 RPM, with down force rangesfor example of between about 0.5 to 60 pounds (2 to 133 N) or more, withuser programmable sweep and force parameters.

The system includes, in some preferred embodiments, a slurry delivery.The slurry delivery can be, for example, standard: 2 peristaltic-typepumps per table, with 1 deionized water rinse, with options of up to 6pumps per table, with a closed-loop flow control, a flow range of slurryequal to about 10 to 500 mL/min., a flow range of deionized water equalto about 50 to 1000 mL/mm, and a slurry pH range of about 2 to 12. Arinse station 256 can further be included with cleaning sprays for waferand wafer carriers that are located between tables 1 and 2, with userconfigurable spray recipe.

The system typically includes a turret for each spindle, though morethan one spindle could be arranged with each turret for polishing morethan one wafer on each table simultaneously or separately. These turretsare independently controlled, indexed and oscillated, and allow forcontinuous rotation. The polishing spindles 240, 242 utilize a downforce range of between about 25 to 1000 pounds (111 to 4448 N), with aspeed range between about 10 to 180 RPM. Each spindle includes a wafercarrier 244, 246 that, in this embodiment, carry wafers of between about200 and/or 300 mm with spherical gimbaling mechanism. These carriershave pressure zones between about 1 to 3 (for uniformity control), wherewafer polish and retaining ring forces are recipe controlled.

The system further includes a wafer unload station 232 with water hovernozzle wafer contact or edge contact. In some preferred embodiments, theunload station includes integrated spindle and retaining ring down forcecalibration. This down force calibration allows for the calibration ofthe down force of the spindles during the unload wafer sequence or atother user-specified times. Wafer front and back side sprays can furtherbe included along with carrier cleaning sprays. The unload station canalso utilize a wafer sensor 26.

In some embodiments, the polishing can be implemented through apolishing recipe. The recipe is a 10 programmable steps per polishtable, that is user-configurable, each step, for: polish time, downforce, back pressure, table speed, spindle speed, force ramping,retaining ring force, and slurry flow.

The front-end module 122 includes the robot 220, and can be implementedthrough substantially any relevant robot for transport of wafers, suchas an AdeptSix 300CR CS, 6-axis cleanroom robot, with cleanroomcompatible quick-change tool changer for attaching end effectors. Theend effectors, in some embodiments, are 300 mm or 200 mm, edgecontacting type or 200 mm, 150 mm, or smaller, backside vacuumcontacting type. Wafer input and output utilizes, in some embodiments,wafer carts 126 to mechanically dock with front-end module, where theinput is dry and the output is wet.

In some implementations, the system includes a light tower having, forexample, four colors (red, yellow, green, and blue) and/or audiblesignal to indicate different processing conditions. Additionally and/oralternatively, a graphical user interface can be employed, such as acolor touch screen control.

FIG. 31 depicts a simplified, isometric view of a system 3110implemented according to the parameters specified above. The system 3110includes the processing module 3122 and front-end module 3124. Thefront-end module further includes the robot and end effectors 3126, andthe send and receive cassettes 3130, 3132. The processing moduleincludes the load and unload stations 3140, 3142, the first and secondtables 3144, 3146, and first and second spindles with wafer carriers3150, 3152.

FIG. 32 depicts a simplified, overhead view of a system 3210 accordingto some embodiments. This system allows for wafers to be removed dryfrom the input cassette 3212 and deposited in the output cassette 3214wet. The robot (not shown) utilizes dry end effectors to remove a waferfrom the input cassette 3212 and transfer it to the transfer station3216. The robot switches end effectors, retrieves the wafer and deliversthe wafer to the load station 3220. One of the spindle/carriers 3222,3224 collects the wafer from the load station and initiates processing,for example, by polishing the wafer on the first polish table 3232.Following the polish, the wafer can be rinsed in an optional rinsestation 3236 and polished again on the second polish table 3234.Following the polishing, the wafer can optionally again be washed, andis then delivered to the unload station 3240. The wafer may be furtherrinsed at the unload station. In some embodiments, the polish pads 3232,3234 are conditioned with pad conditioners 3242 during polishing(INSITU) or between polishing (EXSITU). In some embodiments, the robotcan flip the wafer for processing on the reverse side. The robotretrieves the polished wafer from the unload station 3240 with the wetend effectors and can optionally measure the wafer, for example, with awafer scanner when included or simply position the wafer into the wetbasin output cassette 3214 without being further dried. Some embodimentsadditionally include a temporary wet buffer 3252 that allows processedwafers to be vertically stored while the basin is being replaced and/oris full. Again, the six axis robot 220 allows for the rotation of thedisk into the vertical position. If is often preferable to store wafersvertically, especially when storing them wet so that particles do notsettle on the surface. An additional end effector 3250 can be includedin some embodiments, such as a wafer scanning wand that allows manydifferent configurations on the tool changer of the robot to use.

The system 120 can, in some implementations further include componentsfor measuring and/or calibrating the spindle force, wafer force and/orretaining ring force as applied through the carriers 244, 246. Forexample, the unload station in some embodiments includes one or moreload cells for use in detecting pressures applied by the carrier and/orwafer when the carrier deposits the processed wafer into the unloadstation. FIG. 33 depicts a simplified cross-sectional view of an unloadstation 232 according to some implementations incorporating load cellsfor use in determining forces applied by components of the wafer carrier244 and spindle 240. A load cell is a transducer that converts a loadacting on the load cell into an electrical signal. The load cells can beused to measure and/or calculate one or more of the total spindle force,a retaining ring force component, and a wafer force component.

The unload station 232 can include two load cells 3322 and 3324 and aredesigned to distinguish between total downward force from the spindle240 and the force acting on the wafer. A first load cell 3322 measuresthe total downward force applied by the spindle to the wafer carrier 244through an actuation system, such as a bellows, piston, cylinder and/orother such actuation system. A secondary load cell 3324, or plurality ofsecondary load cells (the unload station 232 of FIG. 2 shows threesecondary load cells 3324), measures the force component acting on thewafer in a carrier exerted through a back plate or an inflatablemembrane; wafer force. A load plate 3326 (not shown in FIG. 3) withstandoff or offsets 3 is placed in the unload station. Duringcalibration of the spindle force, pressure in a retaining ring seal orinflatable membrane is set to zero, as further elaborated below. Thecarrier 244 is brought down on the mechanism and placed in contact withboth a ledge around the inner diameter of unload station's guide ring3330 and the load plate 3326 with downward force generated by theactuation system of the spindle.

The first load cell 3322 measures this downward force and a localprocessor, a central controller or computer records the measurements andthe corresponding fluid pressure within the bellows of the spindlecorresponding to the downward force. The fluid pressure in the bellowsis measured for example by an electro-pneumatic transducer. Theresulting force from the bellows acting on the spindle can also bemeasured by beam load cell located in the spindle assembly. Measurementsfrom the beam load cell can be used to calculate spindle force.Measurements from the beam load cell are also compared to measurementsfrom the first load cell 3322.

The load plate 3326 is further used to transfer downward force acting onthe wafer in the carrier to the secondary load cell(s) 3324. The waferforce component may be generated from a back plate or an inflatablemembrane having a membrane pressure. The secondary load cell(s) 3324 areable to measure the wafer force component of the downward force. Forcemeasurements from the spindle and wafer are sent to the controller orcomputer. Spindle force, wafer force, and retaining ring force are thenappropriately calibrated with corresponding pressures using a spindleforce equation:

(F _(spindle) =F _(wafer) +F _(retaining ring)).

FIG. 34 illustrates the three forces considered during CMP polishing.These forces include, spindle force 3420, wafer force 3422, andretaining ring force 3426. Downward force from the spindle 240 acts onthe wafer carrier 244. The force acting on the carrier is split in thewafer carrier to a retaining ring force 3426 component and a wafer force3422 component. The force balance equation of these forces isrepresented as follows:

F _(spindle) =F _(wafer) +F _(retaining ring);

where F_(spindle) equals force from the spindle acting on the carrier;F_(wafer) equals a portion of force from the spindle acting on thewafer; and F_(retaining ring) equals a portion of force from the spindleacting on the retaining ring. Since wafer force 3422 plus retaining ringforce 3426 is substantially equal to the total spindle force 3420, oneof these force values can be calculated by knowing values for the othertwo of the three forces in the equation.

The system 120 applies a spindle force at a desired set value. Theactual force of the spindle is measured with the first load cell 3322.The system also is able to measure wafer force component using thesecondary load cell(s) 3324. Retaining ring force can then be calculatedby subtracting the wafer force component from the total downward spindleforce (i.e., F_(retaining ring)=F_(spindle)−F_(wafer)). Retaining ringforce can be calculated to generate a calibration curve relating to theretaining ring seal pressure.

The spindle force typically is generated from an actuation system. Theactuation system may be pneumatic, hydraulic or some other system. Forexample, pneumatic actuation of a spindle can be achieved through theuse of a bellows. The bellows actuate a mechanism that pushes thespindle coupled to a carrier towards a polish pad during polishingand/or toward the unload station during unload. The spindle force isdivided in the carrier into the retaining ring force component and waferforce component. These two components from the carrier act on the polishtable during polishing.

Some wafer carriers utilize a retaining ring seal behind a retainingring. In some wafer carriers, such as Strasbaugh's ViPRR carrier, thesemiconductor wafer is held by the carrier while a retaining ring sealsituated behind a retaining ring is pressurized. The pressurizedretaining ring seal presses against the retaining ring affecting theretaining ring force. An equation or table is used to determine theamount of air pressure used in the inflatable ring seal to generate thedesired amount of force on the retaining ring during wafer processing.The present calibration system of the present embodiments allows thepressure from the inflatable seal to be calibrated in order to achievethe retaining ring force by taking measurements of the wafer force whenthe spindle force is set to a known value. In other wafer carriers, theretaining ring is held by the carrier, while an inflatable membrane isused to apply pressure behind the wafer. The inflatable membrane in thisconfiguration generates a wafer force which is a component of thedownward force acting on the wafer. Other wafer carrier configurationsmay use a back plate to apply a wafer force. An equation or table can beused to determine the amount of air pressure to supply in the membraneto apply a desired force on the wafer during polishing.

The calibration system allows a quick and accurate method to calibratethe spindle bellows or other actuation system, inflatable seal(s), andmembrane pressures with corresponding spindle force, retaining ringforce, and wafer force in the system before or after a polishing. Thiscalibration method and system result in the use of more accurate forceswhile polishing wafers. FIG. 35 shows a simplified flow diagram of aprocess 3520 for use in calibrating spindle forces. When the calibrationis employed, a load plate 3326 with offsets 3 is placed in the unloadstation 232. Typically, the offsets 3 of the load plate 3326 aresituated above a load cell or plurality of load cells 3324 located inthe unload station. The offset 3 can be adjustable and the height of theload plate 3326 can be adjusted to compensate for wafer thickness.Pressure in the retaining ring seal or inflatable membrane is set tozero, depending on the carrier type. This way, a spindle forcemeasurement unaffected by ring seal pressure or membrane pressure can betaken. A spindle 240 with a carrier 244 is then positioned above anunload station in step 3522. The wafer carrier can be loaded with a testwafer or alternatively, the wafer carrier can be empty depending on theconfiguration of the load plate.

In step 3524, the actuation system of the spindle is pressurized. Instep 3526 the wafer carrier is brought down onto the unload station witha certain amount of downward force. The unload station, can in someembodiments, have some degree of freedom horizontally in the x and ydirection (e.g., through linear bearing rail assemblies) and itsconfiguration is such that it is self-centering with the spindle andcarrier. This enables the carrier to align itself with the center of theunload station. When the wafer carrier is brought down onto the unloadstation, it is placed in contact with the load plate and ledge 3330around the guide ring in the unload station.

In step 3530 a controller activates the actuation system to a specifiedpressure creating the downward force of the spindle to calibrate thespindle force. Pressure in a wafer carrier's inflatable ring seal orinflatable membrane is at zero. In step 3532, the actuation systembrings the wafer carrier down to the unload station and the first loadcell 3322 is then used to measure the resulting spindle force created bythe actuation system. In step 3534, the controller records themeasurements from the first load cell and the respective bellowspressure that generated that spindle force. In step 3536, the controlcomputer then repeats this process for various pressures in theactuation system and records the pressures and corresponding spindleforce. In step 3540, a bellows pressure or piston pressure versusspindle force curve is generated. FIG. 36 illustrates a spindlecalibration curve created using the data collected for bellows pressureor piston pressure versus spindle force.

In step 3542 the controller commands the spindle force to a specifiedamount bringing the wafer carrier down onto the unload station Tocalibrate fluid pressure corresponding to force components in the wafercarrier such as retaining ring force or wafer force. In step 3544, thecontroller then sends a command to inflate the retaining ring seal or toinflate the inflatable membrane, depending on the carrier configuration,to a certain amount of pressure. In step 3546, the first load cellmeasures the total amount of spindle force and the second load cell(s)measures the wafer force component of the spindle force. In step 3550,the controller tests and records force data for a variety of ring sealor membrane pressures. The controller uses the total spindle force andwafer force components to calculate the retaining ring force. In step3552, the process is repeated to generate a number of forces. In step3554, a seal pressure versus ring force or membrane pressure versus waveforce curve is generated. FIG. 37 depicts a calibration curvecorresponding either to the inflatable ring seal pressure that generatesa retaining ring force or the inflatable membrane pressure thatgenerates a corresponding wafer force. For example, FIG. 37, shows acalibration curve for a VIPRR wafer carrier having an inflatable ringseal.

The calibration curves of FIGS. 36 and 37 generated by the aboveprocedure are generally unique to the tested wafer carrier and spindle.The calibrated spindle and carrier can then be used during the waferpolishing process. The calibration helps in attempts to ensure that thespindle force, wafer force, and retaining ring forces are correct duringwafer processing.

Calibration should occur when desired or needed. It can be performedwhen a carrier 2 is replaced with a different carrier, when theretaining ring and/or retaining ring seal are replaced, or when heightsof carriers are adjusted (retaining ring height is set using shims—asthe ring wears, the height must be shimmed-up). Wafer carriers have manyconsumable items (including retaining rings and retaining ring seals)causing periodic servicing. As such, it is common for the carriers to beremoved, rebuilt, and replaced periodically. Calibration is typicallyperformed after rebuilding the carrier. Similarly, the calibrationprocess can be run when the wafer carrier is changed in the system. Inaddition, calibrations tend to drift over time. Periodic calibrationscan be beneficial even when carriers are not changed or rebuilt.

The wet basin 3214 can be raised from the basin holder. The front-endmodule 122 can be configured to allow a wet cart to dock with and/or beinserted into the front-end module. The cart receives the wet basincontaining the processed and still wet wafers for transporting thewafers for cleaning, further cleaning and/or other processing.

Some implementations of systems according the present embodiments areconfigured to comply with specification, such as specifications of thedocument Titel 50 (Technologische Ausrustung fur Wafertechnologien)′ Los50.8.00. These systems can provide a hazefree polishing of, for example,300 mm silicon wafers and through the developed CMP system to allow thepolishing of the front and/or backside, without flipping the wafer inthe box. In some preferred embodiments, the system is implemented as asingle-side polisher, such that the wafers are flipped by the robot toprovide second-side polishing capability. These systems include, forexample, two polishing tables 234, 236, two wafer chucks 244, 246,handling robot 220 for transfer between load station 230 (dry input),polisher 234, 236 and unload station 232 (wet output), pad conditioner262 for each table (nylon brushes and diamond for silicon haze freepolishing), and cleaning station 224/256 for chuck and wafer cleaning.The carrier and/or wafer cleaning station 256 are utilized betweenpolishing on table 1 and table 2. The cleaning station employs sprayclean, but some embodiments utilize brush cleaning. An output station isfurther included for depositing the processed wafers by the robot andend effector. In some embodiments, two end effectors are utilized whereat least one is submergible. A retaining ring utilizing “floating” and“fixed” retaining ring technology can be employed, in some embodiments,with the same carrier, providing conversion within 10 min. Wafers withthickness between about 650-780 μm can be processed without changing thecarrier tool (floating and fixed retaining ring). The pad conditionersutilize sufficient water supplier at the place of the brush (maximumdistance 10 mm), with sufficient cleaning of the brush after theconditioning process. The brushes are kept wet in some implementationsduring standby modus.

The wafers are processed in some embodiments including: placing a waferat a first polishing table 234, a wafer and polishing chuck rinsing,polishing at the second polishing table 236, wafer and polishing chuckrinsing (Wafer pre clean), wet unload station 232, and chuck clean. Analternative process sequences could include, after polishing, wafers arestored in a wet buffer, where wafers are cleanable by standard siliconcleans.

Preferred embodiments allow for continuous operation. The continuousoperation of the system, with no break between successive boxes, isachieved, in some implementations, by two input stations and two outputstations or alternatives/output buffer for at least 2 wafer buffer withone output station. The system can be supplied with two input and twooutput stations, or with a wafer buffer (e.g., minimum two wafercapacity) to ensure continuous, uninterrupted operation of the machine.In some embodiments, the “cart” supplied for the output shall containwater and an empty cassette.

In some embodiments, the input stations are Crystal Pak 13 wafers(Entegris), and the output station is a transportable wet buffer. Thewafers are placed into low mass carriers, for example, one low masscarrier contains 26 wafers, in vertical positioning. The transportablewet buffer is docked to the wafer cleaning tool.

The system can include a stand-by mode. In some embodiments, the systemwets critical components, such as the polishing tables; wafer cleanstation; chuck cleaning station; chucks (wafer backing film); andpolishing conditioner are sprayed or otherwise kept wet during standbymode.

The slurry flow supplied to the polish tables can be supplied, in someimplementations, at rates of between about 10-1500 ml/min on bothtables. In some implementations the slurry flow is between 200-300ml/min. Two slurry pumps can be provided for each of the primary polishtables pumped in the range of about 4.8-480 ml/min. or 17-1700 ml/min Insome implementations one of each type of pump is supplied on each tableto provide maximum flexibility.

The polishing control includes measurements of the polishing pressure,current and temperature; with an interface for data transfer to bespecified (communication protocol, data sampling frequency, etc.). Thesystem collects and stores data within the machine in log files, and caninclude SECS/GEM communication capability to download the data files toa third party software or a factory host. SECS/GEM is a standardplatform for communication with factory hosts and for data transfer. XMLcommunication is additionally and/or alternatively provided in someimplementations.

Measuring instruments (inspection, measuring and test equipment andsoftware) allow the system to conform with quality requirements forcontrol and calibration in regular intervals and that these calibrationsare typically traceable to accepted international and nationalstandards. In cases of faulty calibrations, some embodiments includeadjustment features to adjust the equipment (hardware and/or software).These adjustments are typically secured against alterations. Theprocesses of adjustment are in some embodiments automatically runthrough self-adjustment on particular test objects (height standards,gauge block, etc.) which are certified traceable to standards (e.g. DKD,NIST, PTB, etc.).

Some embodiments achieve wafer processing to satisfy at least thefollowing criteria: average haze <0.08 ppm (3 mm edge exclusion); hazehomogeneity: Maximum value 0.08 ppm, delta haze 0.01 ppm (3 mm edgeexclusion); no contamination, no chuck marks, no scratches on front- andbackside (including edge exclusion area); wafer edge: no damage, nocontamination; and metal contamination (VPD-AAS, three wafers): Na, Al,K, Cr, Fe, Ni, Cu, Zn, Ca<5 E 9 at/cm2. Similarly, wafer quality can betested utilizing 50 wafers for inspection after cleaning. Measurement ofthe geometry (thickness, bow, warp, TTV) before and after the haze freepolishing process (silicon removal>=2.0 μm). The specifications to befulfilled by the wafers include: change of TTV<0.2 μm; site flatnessSFQR<0.30 μm (incoming wafer SFQR < or = to 0.20 μm); within Wafer nonUniformity WIWNU (1 sigma)<5%, where the above specifications are at 3mm edge exclusion.

Referring back to FIG. 29, the system 2910 is configured as adry-in-dry-out (DIDO) system such that the wafers are retrieved dry fromthe cassettes, FOUPS or other storage unit 126, and returned dry to thesame or different storage unit. In implementing a DIDO front-end 124,the front-end module can be configured from materials that resistcorrosion associated with expected chemicals used during processing, tomeet industry and safety standards, provide a user interface, havereduced footprint or cross-sectional area, satisfy cleanliness levels ofISO Class 2 or better, easily retrieve and return wafers to storageunits, utilize separate wet and dry end effectors, meet power limits,provide off system communication, provide reporting or cooperate withexternal device to generate reporting. Some implementations optionallyinclude a measurement system, a wet buffer station, and/or a cleaner.FIGS. 38 and 39 depict simplified overhead block diagrams of a two FOUPfront-end module 3820 and a three FOUP front-end module 3920,respectively, according to some implementations that satisfy the abovelisted DIDO front-end criteria.

Because of exposure to chemistries and deionized water the material usedin constructing and assembling the front-end modules 3820 and 3920 areselected to withstand contact with such chemicals and deionized water.For example, components can be made of:

plastics resistant to expected chemistries including, but not limitedto, Polyethylene Terephthalate (PET), Polyetheretherketone (PEEK),polyphenylene sulfide (PPS), stainless steels (e.g., 300 seriesstainless steel, 17-4 PH stainless steel and the like), anodized and/orTeflon coated Aluminum, powder coated Aluminum, powder coated steel can(e.g., for use with non-wetted components such as the frame, and othersuch materials. Similar materials can also be used in the polishingmodule 122 cooperated with the front-end modules 3820 and 3920 forcomponents such as, but not limited to fittings, valves, tubing,hardware, and other components.

The DIDO front-end modules and their components are designed andconstructed to meet and/or exceed expected industry safety standards,such as semiconductor equipment and materials international (SEMI)standards S2, S8, and F47, CE standards, Factory Mutual ResearchCorporation (FMRC) (e.g., FM 4910) and/or other standard. Further, thefront-end modules are constructed such that electrical components usedare not exposed to splashing and dripping of chemicals and/or deionizedwater. The cleaner and the handling section of the front-end can providea panel mounted connector for integrating (through CE compliant devices)connections for an emergency off (EMO) circuit(s). EMO circuitactivation, the front-end (and in some implementations the processingmodule) typically remove electrical power to potentially hazardcomponents. Typically the front-end module, as well as the processingmodule, include lights (e.g., user configurable light tower) to providean adequate level of lighting within the front-end (and processingmodule). A CE compliant interlock system is incorporated into doorentries into the front-end module and these are separate from the EMOcircuit.

A user interface, in some embodiments is implemented through a graphicaluser interface (GUI) monitor. In some embodiments a Strasbaugh GUImonitor is used (e.g., part number 300637, providing 110 VAC, touchscreen operation, 15″ minimum monitor, color display, SEMI compliant forlocation, includes removable memory storage (e.g., compact disc drive,digital versatile disc drive, floppy drive and/or other drives) allowingstoring and importing of data, software and the like (e.g., for recipeportability). In some embodiments, the primary GUI is located on thefront-end module and a secondary GUI can be located in processing moduleor remote from the system. A switch can be used to toggle control of thetool from one GUI to the other, however, typically one GUI controls thetool at a given time.

The GUI displays in fixed units, a mixture of metric, English and/or SIunits as appropriate. In some embodiments, the GUI further provides forgraphical wafer tracking indicating where there are wafers in the system120.

The footprint of the front-end module 3820, 3920 is kept relativelysmall and in some instances to a minimum. For example, the two FOUP FEM3820 (not including the optional cleaner and particulate measurementsystem) can be 79.5″(width)×31.5″(depth)×89″(height) (these dimensionsdo NOT include the protrusion of the pod door openers from the front ofthe enclosure).

As introduced above, some front-end modules are configured to have acleanliness level of ISO Class 2 or better (under Class 1000 or betterambient conditions), as measured 4″ above the wafer surface alongregions or places where the wafer track within the front-end.Verification of this cleanliness can be performed with the front end drystate. Positive pressurization and air flow can be employed such thatthe front end remains clean and is not contaminated by the polishingmodule or when an operator door is opened. A minimum pressure differencebetween inside and outside the front end can be maintained, e.g., atabout 0.01″ H₂O with maintenance doors closed and at about 0.004″ H₂Opressure difference when the maintenance doors are open.

The wafer input and output for the DIDO front-end modules 3820, 3920 istypically FOUPs and other similar carriers. Some embodiments furtherinclude wafer cassette scanning that is integrated into the FOUP dooropening mechanism. The scanning method can be implemented, for example,through-beam type. Similarly, other configurations of the tool may useSMIF or open cassettes (wet and dry).

As detailed above, the robot utilizes one or more end effectors forremoving a wafer from the FOUP, transporting the wafer and returning thewafer to the FOUP. A multi-axis robot is used to move wafers to and fromthe various stations within the front-end module. The robot can beconfigured to retrieve or place a wafer in between two other wafers in aFOUP. In typically operation, the robot draws the highest or the lowestwafer (e.g., customer-selectable) and proceeds down or up through thewafers of the FOUP, respectively. Typically, the end effectors areimplemented as edge contacting effectors. The integrity of the waferslot is maintained. The robot is further configured to avoidcontaminating clean, dry wafers with water. Therefore, the clean, dryend effector is used to enter an opened FOUP. The followingconfigurations and/or methods can be used to accomplish this: use twoseparate end effectors mounted on one or two arms for dry and wethandling; use two separate robots, one for dry and one for wet waferhandling; and/or use one end effector and incorporate a method to cleanand dry that end effector. Typically, the wet end effector is configuredto be able to flip wafers 180 degrees. The wet end effector can besaturated with deionized water and diluted slurry as it reaches into thepolish section of the machine and thus is typically configured to becompatible in a wet/corrosive environment (but may be exposed to a muchlesser degree when an optional end effector and flipper mechanism isemployed).

The measurement system can be implemented through one or more devices,such as a Nova Measurement System (e.g., Nova 3030 Measurement System)that is incorporated into the front-end module for pre and/orpost-polish measurement of wafers. The measurement system is typicallyan optional feature. Measurement recipes are user-configurable throughthe software (e.g., Nova software). The GUI for the measurement deviceis integrated within the GUI touch screen. Either a manual switch or keycan be used to access the measurement system control screens. Handlingcomponents located above the measurement system can lower and raisewafers into and out of water, and provide the wafer I/O point for therobot. The measurement system handler contacts the wafer by the edgesand/or by using a vacuum style chuck or end effector, and the waferhandling components can also be used as a wet buffer station for wafers,as well as a location to transfer from dry to wet end effector handling.Some embodiments notify the operator via configurable alarm when themachine halts due to back-ups at the measurement system, and/or caninclude closed-loop control (CLC).

The optional wet buffer station can be included to avoid a wafer from todrying prior to being cleaned. The buffer station can contain at leastenough slots to hold a defined maximum amount of wafers that could be inprocess at any given time. For example, this number of wafers for thebuffer is eight (8). Sprayers can be strategically placed relative tothe buffer to keep the surfaces of the buffered wafers wet. The wetbuffer station can be used when the cleaner or measurement system is notimmediately available to clean or measure a wafer, in the event of amachine malfunction, an automated sequence places the in-process wafersin the wet buffer, which can then be cleaned and placed back in theFOUP's, and other situations or scenarios.

The optional cleaner, in some embodiments is implemented for example,through a Contrade's Corwet cleaner. The Corwet includes its owncontroller and software, and is permissible to either integrate thecleaner using its controller, or to control the unit using a controllerin the system. A cleaner GUI is be integrated into the system GUI. Amanual switch or key can be used to toggle between the cleaner andsystem GUI environments. The Corwet's software may be integrated intothe system software. The cleaner can be configured to safely handle HFchemistry.

A wafer sequencing process for wafers before polishing can include:remove wafer from FOUP cassette using dry end effector (assume wafersare device-side UP in FOUP); place wafer in transfer station; shift towet end effector; remove wafer from transfer station using wet endeffector; flip wafer (e.g., device-side is now down); place wafer inload station 230; wafer is picked-up by spindle 240/carrier 244 forpolishing (e.g., for a polishing time equal to about 2.5 minutes);unpolished wafers are to continually be placed into load station (as itbecomes available) in preparation for polish. A wafer sequencing processfor retrieving wafers after polishing can include: after polishingspindle/carrier places wafers in the unload station 232; remove waferfrom unload station using wet end effector; place wafer in measurementsystem; measure wafer (e.g., process time of about 1 minute); removewafer from measurement system using wet end effector; flip wafer (e.g.,device-side is now up); place wafer into cleaner; cleaner scrubs wafer(e.g., process time of about 1 minute); switch to dry end effectors;remove wafer from cleaner using dry end effector; place wafer in FOUPcassette; polished wafers are to continually be moved from unloadstation to FOUP. Variations to the above Sequence(s) can include: thatthe measurement system measures polished wafer, determines it is out ofspec, and the wafer may be placed back into load station for re-polish;measurement system may measure a certain percentage of polished wafers,where some percentage of wafers may go directly from unload station tothe cleaner (skipping the measurement system); some or all wafers may bepre-measured by the measurement system, such that wafers are taken fromthe FOUP with the dry end-effector, placed in the transfer station,picked-up with the wet end-effector, flipped, and then placed in themeasurement device for measuring, where after measuring, the wafers areplaced in the load station; and/or other variations.

The process times given above are examples of processing time, but canvary depending the processing, type of wafer, and other parameters. Insome implementations, the processing times are usable configurable. Forexample, polishing times can typically vary between about 1 to 5 minutes(2.5 minutes is common, but overhead adds another −0.5 min); measuretime can vary between about 1 to 2 minutes (1 min is common); cleantimes can vary between about 1 to 2 minutes (1 min is common).

Power supplied to the front-end module can vary. For example, powersupplied to the cleaner and front-end handling section by the system canbe 208, 380, or 460 VAC, 3-Phase. Typically a single point powerinterface is utilized. The system 120 additionally can include datacommunication capabilities. Data transfer between the processing modulecontroller and the front-end module controller can occur through an RJ45connector and utilizing Ethernet TCP/IP protocol. The front-end modulecan include other interface connections such as EMO circuit, stopmotion, GUI and the like. The front-end must tracks wafer movementwithin the cells, and provide feedback to the system controller orcentral processing unit. Commands to the front-end from the systemcontroller typically occur at high levels, while movements of componentsin the front-end can be controlled by an independent controller in thefront-end. The front-end controller can be physically located in thefront-end module. Further, the FOUP PDO's can have an E84 parallelinterface to communicate with the OGV handling unit.

The configuring of the system 120 in two components, the front-endmodule 124 and the processing module 122 allow the system to be moreeasily transported. Further, the two modules allow the system to be moreprecisely customized for a specific user implementation. Still further,the separable modules allow one module to be constructed (e.g., theprocessing module) while the other module (e.g., the front-end module)is being designed.

Some present embodiments may be further understood in view of U.S.patent application Ser. No. 11/046,502, filed Jan. 28, 2005, entitledChemical-Mechanical Planarization Tool Force Calibration Method andSystem, incorporated in its entirety herein by reference, and U.S. Pat.Nos. 6,045,716, filed Apr. 4, 2000, and 6,354,926, flied Mar. 12, 2002each incorporated herein by reference in their entirety.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations could be made thereto by those skilled in the art withoutdeparting from the scope of the invention set forth in the claims.

What is claimed is:
 1. A system comprising: a front-end module thatcouples with a storage device that stores objects for processing, thefront-end module comprising: a single robot; a transfer station; and aplurality of end effectors; and a processing module coupled with thefront-end module such that the single robot delivers objects from thestorage device to the processing module, the processing modulecomprising: a rotating table; and a spindle with a carrier configured toretrieve the delivered object and process the object on the rotatingtable.
 2. The apparatus of claim 1, wherein the front-end module furthercomprises a wet basin that receives the object after being processed. 3.The apparatus of claim 2, wherein the front-end module further comprisesa portable cart that is independent of and couples with the front-endmodule such that objects are delivered from the wet basin of the frontend to the portable cart.
 4. The apparatus of claim 1, wherein theprocessing module comprises a load station at which the single robotdelivers the object to the processing module.
 5. The apparatus of claim1, further comprising a tool changer to change between the plurality ofend effectors.
 6. The apparatus of claim 5, wherein the plurality of endeffectors comprise a wet end effector to grasp and transport wet wafersand a dry end effector to grasp and transport dry wafers.